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(No Model.)

' R. T. MARTIN.

NUMERAL FRAME.

Patented June 12,1883;

.Ewvenfbor Wibrwss as if/ y UNITED STATES PATENT OFFICE.

ROBERT T. MARTIN, OF TORONTO, ONTARIO, CANADA.

NUMERAL-FRAM E.

SPECIFICATION forming part of Letters Patent No. 279,263, dated June 12,1883.

Application filed May 15, 1882. (No model.)

To all whom it may concern:

Be it known that I, ROBERT T. MARTIN, a citizen of the Dominion ofCanada, residing at 26 Montague Place, in the city of Toronto, in theProvince of Ontario, have invented a new and useful Calculator orNumeral-Frame, of which the following is a specification.

The obj ect of the invention is to provide an educating-toy forchildren; and it consists, essentially, in a grooved frame having markedupon its face figures representing the digits. Above the said frame anumber of balls are strung upona wire, and within a groove formed in theframe slide a series of dovetailed blocks, each of which has marked uponits face one of the digits. By moving the series of blocks in onedirection and placing the liberated block from one end back into thegroove step by step, a perfect addition-table is made, while by movingany number of balls away and counting those remaining asubtraction-table for beginners is obtained.

In the accompanying drawings, Figure 1 is a perspective view of thedevice merely as a toy; and Fig. 2, a similar view, showing thedeviceattached to an ordinary school-desk.

Referring to the drawings, A represents the base plate, having alongitudinal bridgepiece, B.

' G are cleats or strips nailed or otherwise secured on either side ofthe bridge-piece B, and forming on either side thereof a dovetailedgroove, in which the dovetailed blocks D are adapted to slide. Upon theupper of these cleats, on either side, are marked the digits, only fivebeing shown in Fig. 1, and each of the blocks .D is marked with one ofthe digits, as shown. The blocks may be locked in position, with anydesired arrangement thereof,

by means of a button, E.

F represents the wire, secured to the top of the bridge B, upon whichare strung the balls G.

It will be observed that the symbols on the blocks D are each below aparticular digit on the cleat. Each two may therefore be added togetheror subtracted, and by loosing the button E and forcing the series to theright or left a complete change is made. It will also be seen that asthe grooves between the cleats are open at both ends, a. block may bereadily removed from one end of the groove and placed in the other end,whereby the blocks may be more readily adjusted in the desired positionthan where the grooves are closed at one end, or are connected withother grooves through which a block has to be moved before it can beplaced in the other end of the groove from which it was taken. Theaddition of the buttons will be found to be a great convenience, as bytheir use the blocks can be easily and quickly secured in the grooves.This construction will not only produce a toy for amusement, but prove avaluable educator.

What I claim as new is The educational toy herein described, consistingof the bar A, the bridge B, the cleats O, secured thereto to form adovetailed groove open at both ends, the upper cleat upon either sidebeing marked with the digits, the dovetailed sliding blocks D, eachmarked with a particular digit, the button E, wire F, and balls G, asandfor the purposes specified.

ROBERT T. MARTIN.

XVitnesses:

K. M. ALLAN, L. SLATER.

